The present invention relates to a tire position determination system for determining the position of a tire when monitoring the air pressure of the tire.
A direct tire pressure monitoring system is known in the art. In a direct tire pressure monitoring system, each tire includes a tire pressure detector that detects the tire pressure and transmits, through wireless communication, a tire pressure signal. The vehicle body includes a receiver that receives the tire pressure signal from each tire pressure detector. The tire pressure monitoring system monitors the pressure of each tire based on the tire pressure signal. This type of tire pressure monitoring system recognizes the position of each tire is located and determines where a tire having low pressure is located relative to the vehicle body. However, tires may change positions. Further, a tire may be exchanged with a new one. Thus, a direct tire pressure monitoring system may include an automatic locating function that periodically checks the tire positions. Japanese Laid-Open Patent Publication Nos. 2006-062516 and 2012-126341 describe examples of direct tire pressure monitoring systems that realize the automatic locating function by attaching an initiator (trigger device) to each wheel well. The initiators transmit radio waves that result in the tire pressure detectors selectively transmitting radio waves to allow for the determination of tire positions.
However, the automatic locating function is realized by arranging an initiator in each wheel well. Thus, the automatic locating function that uses the initiators increases the number of components and raises the component cost.